Fabric for airships and process of making same



Mar. 27,1923; 1,449,748. H. A. GARDNER.

FABRIC FOR AIRSHIPS AND PROCESS OF MAKING SAME. FILED NOV. 19. 1920.

DI LDDPE ALUMINUM PUWDER /RUBBER LAYER 2 RUBBERSNURATED CLOTH" 1 Patented Mar. 27, 1923.

UNITED STATES PATENT OFFICE.

HENRY A. GARDNER, OF WASHINGTON, DISTRICT OF COLUMBIA.

FABRIC FOR AIRSHIPS AND PROCESS OF MAKING SAME.

Application filed November 19, 1920. i Serial No. 425,190.

To all whom it may concern:

Be it known that I, HENRY A. GARDNER,

, a citizen of the United States, residing at lVashington, District of Columbia, have invented new and useful Improvements in Fabrics for Airships and Processes of Making Same, of which the following is a speci- I fication.

This invention relates to a water and gas proof fabric and method of'manufacturing the same.

An object of the invention is to provide a fabric'wherein the expense of production is greatly reduced in comparison with all other known methods.

In the manufacture of various objects which are required to be; either waterproof or gasproof, such, for instance, as envelopes of non-rigid balloons or gas cells of rigid airships, difficulty has been encountered in securing a relatively inexpensive fabric that is light in weight. The envelopefabric, for instance, used in non-rigids mayweigh as high as 16 oz. per square meter, while the J goldbeaters skin used on the fabric for gas cells of rigid ships may be prohibitive in cost due to the high cost of the materials used and the extensive labor required in the manufacture of the fabric.

I have heretofore produced a fabric as disclosed in my prior Patent No. 1,381,413 consisting of high strength cotton coated with a tung oil dope that dries largely by polymerization to a'fiexible film. This fabric might show a low diffusion. In its manufacture, however, I have found that the first coat of oil dope applied causes the fibres of the thread to become raised and rough or linty surfaces to be presented. Singeing and calendering, as well as the application of additional coats of oil dope, are required to lay these threads. Even with these operations it is not alwayspossible to make a perfectly smooth surface. If the fibres are not properly covered, they act as little pores through which hydrogen or other gases and even moisture may ultimately penetrate. I

have, moreover, found that the direct application of an oil product to a fabric such as cotton, for instance, may injure the fabric and cause it to tear very easily. Such fabric also may become brittle or stifi' on long exposure.

A- suitable method of manufacture Will now be described with reference to the accompanying drawing showing a magnified section of the fabric. I select a grade of thread fiber or fabric which is suitablefor the purpose intended. fabric is desired I prefer either a cotton or a silk cloth of the following construction When a balloon Cotton. Silk. \Veight per square yard 2.5 oz. 2 oz. Vidth 38 in. 38 in... 1 Minimum tensile strength:

Warp 35 pounds. 45 pounds. Filling 35 4:5 Minimum thread count:

Warp 116 Filling 124 I first fill the fabric indicated at 1, with rubber preferably in solution in benzol or a similar diluent. 10 parts of Para rubber and 90 parts of benzol will give a satisfactory mixture. If desired, a small amount of sulphur or other vulcanizing agent may be incorporated (usually less than 1%). The filling of the interstices of the first cloth with this mass may be done by brushing, dipping or coating, preferably with a machine. I generally apply from 3 to 8 coats of this composition toeach side of the cloth until it is well'filled, the pores between the fibers as well as the fibres being covered andrendered into a more or less continuous sheet composition.

The rubber solution is applied in excess to form layers designated at 2, on the outside of the basic material. I then, by any suitable apparatus, dry the fabric by passing the same over. heated pipes. cloth will now show a continuous surface without raised threads. The fabric is then subsequently treated with oneor more coats of oildope to form films 3 on the outside of the layers 2. The application of this dope may be made by brushing, dipping or application on a coating machine. The oil The coated dope used is preferably made on the following formula Ester gum 125 parts. Tung oil 250 Liquid driers; 20 Turpentine 60 Mineral spirits 300 Ester-gum is made from resins such as rosin combined with about 10% glycerine to form a neutral ester.

If desired, I may incorporate a pigment such as aluminum powder with the oil dope 4. The oil dries well over the rubberized surface to an extremly smooth film, free from lint or raised threads. It is usually advisable to make two applications of the oil dope. The fabric produced is extremely flexible and soft, and shows a continuously lower diffusion than any heretofore produced with the exception of that in which goldbeaters skin films are present. On weathering, the fabric remains soft and maintains an extremely low diffusion, as low as .2 liters per square meter having been obtained after exposure for several weeks. Moreover, the fabric does not deteriorate in strength and does not become harsh or brittle. Its weight is about 5 ounces per square meter.

In some instances I may prefer in manufacturing gas cells or similar objects of this fabric to cut the patterns out. of the rubberized cloth, putting the seams together with tape, and then applying the oil dope to the formed object. In any event the result is the same.

\Vithout further analysis, the foregoing will so fully revealthe gist of this invention that others can by applying current knowledge readily adapt it for various applications without omitting certain features that, from the standpoint of the prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention, and therefore such adaptations should and are intended to be comprehended within the meaning and range of equivalency of the following claims. 7

Having now described my invention What I desire to protect and attain by Letters Patent is 1. A gas and waterproof fabric comprising a basic fabric material the interstices of which are impregnated with rubber, and a coalting of drying oil upon said basic materia 2. A gas and waterproof fabric comprising a basic fabric material of cotton the interstices of which are impregnated with rubher and a coating of drying oil upon said basic material. 3. A gas and waterproof fabric compris ing a basicfabric material the interstices of which are impregnated with rubber, to form a coating on the outside thereof, and a coating of drying oil upon the outside of said film of rubber. I

4. The herein described method of manufacturing a gas and water roof fabric which consists in filling a fabric with rubber solution to constitute a basic material, drying said basic material and coating the outside of the material with dope containing an oil of the class which dries by polymerization.

5. The herein described method of manufacturing a-gas and waterproof fabric which consists in filling a fabric with rubber solution containing a vulcanizing agent to constitute a basic material, drying said basicmaterial and coating the outside of the material with a dope containing an oil of the class described which dries by polymerization.

Signed at Washington, District of Columbia, this 31st day of August, 1920.

HENRY A. GARDNER. 

